CHROMOSOME ABNORMALITIES IN RABBIT BLASTOCYSTS FOLLOWING DELAYED FERTILIZATION

Abstract
Rabbit were mated at timed intervals after an ovulation-inducing injection of chorionic gonadotropin. Blastocysts were recovered at autopsy 6 days after mating and examined cyto-genetically for chromosome abnormalities. A marked decrease in the number of blastocysts recovered occurred at delayed ovulation-mating time intervals greater than 10 hr. Thirteen chromosome aberrations arose among 135 blastocysts, examined. Triploidy was the commonest anomaly and was found in 6 instances from rabbits mated 8 and 9 hr. after injection of gonadotropin. Fewer abnormalities occurred at the remaining delayed intervals. In addition, a pentaploid, 2 mlxoplolds, and a trlsomy were obtained from animals mated immediately following injection.